Float valve



July 22, 1941. E, M 'MAY 2,250,130

FLOAT VALVE Filed Nov. 1. 1937` /N VEN TOR Patented July 22, 1941 FLOAT VALVE Edward M. May, Detroit, Mich.

Application November 1, 1937, Serial No. 172,116

4 Claims.

The invention relates to float valves suitable for controlling the flow of liquid refrigerant from the high pressure side to the low pressure side of mechanical refrigeration systems. In such refrigeration systems float control valves of two different types have been employed. In one type, the float is arranged on the outlet or low pressure side of the valve while in the other type the float is arranged on the inlet or high pressure side of the valve. to the second type of construction.

Refrigeration systems employing the high side iioat control valves have been subject to a serious difficulty in operation, namely, thatrair or other non-condensible gas in the system tends to accumulate in the float chamber. of the valve and interfere with the proper operation of the valve. In such systems an effort is made, of course, to avoid the presence or entrance of air or other non-condensible gas but due to imperfect removal of air and gas at the outset or to leakage of air into the system during operation, the diiiculty referred to is likely to be encountered and has constituted a serious drawback in the use of the high side iioat valve system.

The chief object of the present invention is the provision of an improved control valve with high side float which is adapted in operation to automatically purge air or other non-condensible gas from the high side of the system by discharging it past the ,valve into the low side of the system so that serious accumulation of such gas in the iioat chamber, with resultant interference with the operation of the system, is completely obviated.

Other objects, more or less incidental to the main object referred to, as well as the manner in which all of the objects are attained, will be apparent from the following description in connection with the accompanying drawing which illustrates two of the preferred embodiments of the invention. Y

In the drawing,

Fig. 1 is a longitudinal sectional View, with some parts in elevation, of one form of my improved valve in which the axis of the valve proper and its seat are vertically-disposed, together with a diagrammatic showing of the elements of a mechanical refrgerating system in connection with which the valve is adapted for` use.

Fig. 2 is a similar view of a modified form of valve construction in which the axis of the valve and its seat are horizontally disposed.

Referring first to the valve shown in Fig. l, the device comprises a casing structure desig- The present invention relates nated in its entirety by I and comprising a twopart float chamber structure 2 with a threaded inlet fitting 2a and a valve casing and outlet passage member 3 which is rigidly soldered or brazed to the casing section 2. 4 is a fioat with an arm 5 pivoted on a pin 6 carried by the upper end of the casing part 3. The casing part 3 has its bore fitted near its lower end with a valve seat I and is formed with ribs 8 which serve to `guide a needle valve 9 that is pivotally connected by pin I0 with float arm 5. The outlet passage of the casing structure formed in the part 3 has its main inlet opening II at its upper end surrounding the stem of valve 9 and is provided intermediate its length with a supplementary inlet opening I2 of somewhat restricted capacity, as will later be explained. I3 is a pipe fitting attached to the outlet end of the casing member 3.

In the use of my improved float valve in a refrigeration system such as is indicated diagrammatically in Fig. l, the inlet tting 2a is connected with the liquid refrigerant line I4 of the system which in turn is connected with a condenser I5. The discharge fitting I3 of the valve is connected by conduit I6 to an evaporator Il which in turn is connected by suction conduit I8 with the inlet side of a compressor I9 which delivers compressed refrigerant to the condenser The parts of the'valve mechanism, and particularly the parts 3, 4, 5, B, 'I and 9, are so constructed and operatively arranged that when the level of liquid in the fioat chamber rises to a level somewhat above the line X, the notation force of the float is sucient to overcome the pressure on the Valve 9 and cause the latter to move to lan open position. The valve 9 is subjected to the partially unbalanced pressure of the high side of the system and consequently, in the opening of the valve, the liquid in the float chamber rises above. the level X which is adapted to sustain the valve in open position before the flotation force of the float is sufficient to overcome the unbalanced pressure on the valve. As soon as the valve leaves its seat and the unbalanced pressure on it is removed or largely reduced the float rises quickly to a position of less liquid immersion so that the valve is correspondingly quickly raised well off its seat to a substantially fully open position.

On the opening of the valve in the manner described, liquid refrigerant in the valve chamber B, under the action of gravity and the high side pressure in the system, is forced through the valve seat into the low pressure side of the system. Meanwhile liquid refrigerant flows through passage l2 into chamber B but the caliber of the passage l2 is made suiciently small in relation to the maximum rate at which liquid refrigerant is supplied'through fitting 2a in the normal operation of the system under full load so that, after the opening of the valve 9, the liquid level in the oat chamber continues to rise until the liquid overflows into the opening Il whence it passes the open valve and is discharged to the low side of the system. The capacity of passage i2 is also smaller than that of the valve seat opening when the valve is fully open. Hence before the liquid overows through passage Ii into chamber B and during the restricted flow through passage l2 gas in the space above the liquid in the noa-t chamberA A has access through chamber B to the valve seat opening so that'any air or other non-condensible gas which may have accumulated in theV oat chamber A is atleast in part discharged past the valve and into the low pressure side of the system. In determining the relative sizes of passages I2 and 1, account should of course be taken of the fact that the effective discharge pressure on the inlet end of the passage I2 is much smaller than that of passage 1.

When the supply of liquid refrigerant to the float chamber A is stopped -or sufficiently reduced the level of the liquid in the chamber will begin to fall and the valve S will close upon its seat when the liquid falls to the level X. Then,

' if the valve is not tightly closed, liquid will continue to ow slowly past it until the liquid has fallen to some pointbetween the levels represented by the lines X and Z where the combined unbalanced weight of the float and high side pressure on the valve exert suicient pressure on the valve to seal it tightly. Thereupon the parts are in position for a repetition of the cycle which has been described.

It will be understood that the liquid level at which the immersion of the float is sumcient to open the valver will vary -up or down with variation in the high side pressure of the system. It is to be observed, too, that with the refrigeration system operating under a relatively small heat load the rate of liquid refrigerant discharge into ythe float chamber A may not be sucient to der such lcw load conditions, the opening of the valve occurs in much the same way under low load as under high load conditions. That is, with the valve closed on its seat, the liquid level in the float chamber' A will continue to rise until it reaches some point above the line X before the flotation force is great enough to open the valve,

whereupon the float rises quickly to a higherv level to move the valve to a wide open position. Under such low load operating conditions the opportunity for discharge of accumulated gasv secured by the construction of Fig. 1 is attained in a somewhat different manner yet by the use of the same fundamental principle. In the modifled construction the casing structure 2U comprises a casing section 20a affording a float chamber A and a horizontally disposed valve casing and discharge member 2Gb which aifords a chamber B' for the valve. 20c is an inlet fitting through which liquid is supplied to cham-.- ber A. A float 2l has an arm 22 pivoted on a pin 23 carried by the member 26h. The casing part 2Gb is formed with a valve seat 24 and with ribs 25V which serve to guide a needle valve 2E pivotally connected by the pin 21 with the float arm 22.

The modied valve device is adapted to be connected into a closed circuit refrigeration system in the same manner as the valve first described.

In the operation of the second form of valve, the valve proper is held upon its seat by the pressure in the high side of the system until the liquid level in the oat chamber A rises to some level above that indicated in Fig. 2 by the lineY C. When the liquid reaches such level and the valve opens, by reason of the removal or reduction of vtherunbalanced pressure on the valve 23 the float 2| rises quickly so as to move the valve to a fully open position, as in the case of the first described form of construction. Liquid is then permitted to ow past the valve into the low pressure side of the system. As the liquid levelfalls in the float chamber A the float falls with it and the valve is gradually moved toward its seat. However, the valve does not contact its seat until the surface of the liquid in chamber A falls to the level indicated by the line C which is lw enough to permit any gas above the liquid in the chamber A to find access to the valve seat opening before the valve closes. I-Ience with the second form of construction there is provision forthe discharge from the high pressure side to the low pressure side of the valve during each operative cycle of the valve of non-condensible gas that may accumulate in the upper part of the float chamber A.

In the case of the first form of valve the discharge of gas past the valve is accomplished on the opening of the valve whereas in the second form of construction it is accomplished just prior to the closing of the valve, but it will be seen that in each case the casing structure, valve and oat are constructed and operatively arranged to afford at some time while the valve is open access for gas above the liquid level in the oat chamber to the valve seat opening so that any non-condensible gas that may accumulate in the float chamber is automatically discharged to the low pressure side of the system.

While in the constructions shown the valves proper are arranged to close with the flow rather than against the flow, it is to be understood that the invention in its broader aspects is not limited to this form of construction though I prefer such construction because it does not necessitate the use of a spring or equivalent means to close the valve and permits greater simplicity of construction and lower cost of pro duction.

It will be understood, furthermore, that various other modifications of the construction may be employed without departing from the invention. as defined in the appended claims.

What I claim is:

.1. A unitary high side oat valve for refrigeration systems comprising in combination a casing structure having an inlet passage for liquid refrigerant and an outlet passage for liquid refrigerant and forming a float chamber, a valve seat associated with the outlet passage, a valve arranged to cooperate with the seat to Control passage of fluid therethrough, and means including a iioat in the said oat chamber operatively associated with the valve and adapted to cause opening of the valve when the liquid level rises in the iioat chamber and closing of the valve when said level falls in the iloat chamber, the said outlet passage being constructed and arranged with an inlet thereto opening above the liquid level in the float chamber at which the said means causes closing of the valve so as to afford at a time when the valve is open access for gas above the liquid level in the float chamber to the valve seat opening, whereby in the operation of the Valve gas in the iioat chamber is automatically discharged to the outlet side of the valve seat.

2. A float valve as defined in claim 1 in which the Valve opens against the flow through the outlet passage.

3. A float valve as dened in claim 1 in which the outlet passage of the casing structure has, in addition to the inlet to said passage specified in claim 1, a second inlet opening into it at a level as low as the liquid level at which the Valve closes upon its seat, the second inlet being restricted in comparison with the maximum rate at which the liquid is normally delivered into the float chamber in the operation of the device and of smaller eiectve capacity than the Valve seat opening 4when the valve is in its fully open position.

4. A float Valve as defined in claim 1 in which the valve seat opening and the outlet passage from its inlet end to the valve seat have at least a portion of their diameters disposed above the liquid level in the oat chamber at which the Valve closes.

EDWARD M. MAY. 

